An attempt by the Bush and Kerry campaigns to require that the four moderators of the upcoming debates sign statements saying they've "accepted" the rules drawn up by the campaigns is causing concern among some experts in journalism ethics.

It is "ludicrous," Alan Schroeder, a professor at Northeastern University in Boston and author of Presidential Debates: Forty Years of High-Risk TV, said Wednesday. "These are journalists doing a service to their country. They cover these guys. How can they climb into bed with them?"

Questions about too-close ties between journalists and campaigns are particularly sensitive now because of reports that a CBS producer helped arrange a conversation between a controversial source and an aide to Sen. John Kerry.

The stipulation that moderators for the three presidential debates and one vice presidential debate must accept and sign the rules comes at the end of a 32-page "memorandum of understanding" that details rules agreed to by the campaigns. It was reached in talks between the campaigns and posted on their Web sites this week. If any of the moderators decline to sign, the memorandum states that the campaigns could "agree upon and select a different individual to moderate that debate." Whether the campaigns would enforce that provision is unclear.

The campaigns have decided not to enforce another stipulation in the memorandum: that the independent Commission on Presidential Debates, which sponsors the forums and selected the moderators, also sign the agreement by today. The commission said it couldn't do so because it had previously announced it would wait until Friday to officially determine — based on polls — whether any other candidates should be included in the debates.

The rules cover many issues, including ones as detailed as the exact height of the lecterns to be used at two of the presidential debates (50 inches). They stipulate that audience questioners at the "town hall" debate Oct. 8 in St. Louis must have their questions pre-selected by moderator Charles Gibson of ABC. He is to "cut off" anyone who changes his or her question.

In previous elections, moderators did their best to enforce the rules and regulations agreed to by the campaigns. But they weren't asked to sign a pledge. The difference may not sound important to those outside the news media. But "when you raise questions about your independence, it affects your credibility as a journalist," said Aly Colón, ethics group leader at the Poynter Institute, a school for journalists.

One of the moderators said he'll abide by the request to sign — if the commission decides to accept the ground rules. Bob Schieffer, host of CBS' Face the Nation, said Wednesday that he has "no problem" with the rules. "My job is to show up with a pocketful of questions" to the last debate Oct. 13 in Tempe, Ariz., he said.

The moderator of the first presidential debate, Sept. 30 in Miami, will be Jim Lehrer of PBS. Gwen Ifill of PBS will moderate the Oct. 5 vice presidential debate in Cleveland. Gibson, Ifill and Lehrer all declined to comment.

Messages left with the commission Wednesday were not returned. Spokesmen for both campaigns said it did not seem unreasonable to ask moderators to pledge to enforce the rules.

The source involved in the CBS controversy, former National Guard Lt. Col. Bill Burkett, has admitted he misled the network and USA TODAY about the origin of documents that have since been challenged as likely forgeries. Those documents, if authentic, would add to questions about whether President Bush fulfilled his service in the National Guard. The Kerry aide, Joe Lockhart, said the conversation with Burkett had nothing to do with the documents.